Using your spine strength to lift yourself ----rather than pushing with your arms----raise your torso off the floor just to the belly button.
arch back as much as possible with head and torso, still using the strength of your spine . At the same time, press the belly button into the floor. Your elbows are still tight to your sides, your shoulders are relaxed and down. When views from the side , the angle inside your elbows should be 90 degreees.
